Signal-lamp.



w.;,s. HAMM.

v SIGNAL LAMP.

APPEICATION FILED MAR. 24. 19]?- 1,288,570, Patented Dec.24,1918.

W Maia 1 UNTTED STATES PATENT @FFTCE.

WILLIAM S. I-IAMIVJI; Oil? 'HUBBARD WOODS, ILLINOIS, HSSIGNORTO' THEADAMS&-

IVESTLAKECOMPANY, A CORPORATION OF ILLINOIS.

SIGNAILLAMP.

Sp ecification' of Letters Patent. Patented 30; 24 191 85 Application filed March 24,1917. SeriaINIO. 157135.-

loall-whomit mayconcc'm: v

Be it known that I, WILLIAM S. HAMM, a a

citizen of the United States, and. resident of Hubbar'dlVoods, county of'Cook, and State of Illinois, have invented. certairrnew and useful Improvements in. Signal-Lamps, of which the following; is aspecification and which are illustrated inithei accompanying drawings, forming-a part thereof.

The invention relates to signal lamps of the top draft type, such as are shownlininy Patents Nos. 651,782, ofrJunegl2, 1900, and 1,039,123, of September 24, 1912.

Lamps .of this character. have'heretofore been employed. in situations. where the air currents move in a horizontahor. approxie niately horizontal, direction. In recent railroad practice, however, a. form of'sema phore has come into use in which the lamp is located back of aplate or shieldhaving, considerable vertical dimension. As re; sult air current moving toward the face of such shield break'over the top thereof and descend vertically, or approximately so. Under such conditions the lamp has a tendency to sweat, moisture generated by the flame being condensed upon the inner sur face of the body and of the lenses. This phenomenon results from a disturbance or reversal of the draft, the descending external air currents apparently inducing an outward flow of air through the ports provided in the top of the lamp for the admission of air to support combustion. When this action occurs the vapors are not only permitted to spread to the walls of the lamp, but if an actual reversal of draft occurs they are drawn over to the lamp walls and lenses.

The object of this invention is to overcome the difiiculty referred to. The character of the invention is fully hereinafter pointed out, and is shown in the accompanying drawings, in which Figure l is a vertical central sectional view of the lamp;

Fi 2 is a transverse section on a reduced scale on the line 22 of Fig. 1; and

Fig. 3 is a detail of the top of the lamp showing a modified form of construction.

The body 10 of the lamp may take any desired form, and is here shown, of the type ordinarily used on semaphores. This body is closed at the bottom, its upper portion 11 is shown as contracted in diameter to constitute what is known as the dome. This dome is :providedwith'a plurality of air. in? duction ports .12, 13, representedasarranged in two annular series. flue; 1 1" is located'onthe axis of thebody, pro ecting into the'dome abovethe ports/'12; An annular plate :15, preferably: imperforate; extends from the fiuetoith e side walls offthe dome, and a foraminous. screen 1 6' extends from the. wall 'offthe' dome toith ewall ofith'e flue and. ishere shown as cylindrical Einform.

The upper; portion of the dome: 1'7 is in the form ofatruncatedcone'and open at the.

Ai central: conical top to form an outlet for the-vapors oficom bustion. A concave cap 18 :is mounted alobve the dome 17 for. the. purpose of excluding; rain'and snow from the flue. Asthusifar described, the lampis of known. constructioni An annular cap 19 fits around the conical portion 17 ofthedome and covers theports.

12, .13. The dependingportion of the cap 19' is of greater diameter than the dome and is open at the bottom, thereby forming with the dome wall a chamber 20 through which air gains access to the induction ports. The bottom rim of the cap 19 is flanged outwardly, as shown at 21, this flange being substantially horizontal.

In the modification shown in Fig. 3, in lieu of the cap 19 there is shown an annular plate 22 fitting upon the conical portion 17 of the dome and extending out horizontally above the induction ports 12, 13.

The cross-sectional configuration of the dome of the lamp is immaterial, and may follow common practice, the dome being sometimes circular and sometimes polygonal. In either case the cap 19 or 22 should correspond in shape to the dome.

The outstanding flange 21 or flat cap prevents the disturbance or reversal of the draft by downru-shing air currents, the construction shown in Fig. 1 being the more efficient and especially desirable because it guards the air ports against the entrance of rain or snow.

The precise movements of the air currents cannot be well determined except theoretically. It is my supposition that without a guard flange such as :21 or 22 the descending currents of air, in sweeping across the induction. ports, produce a suction action and cause the troubles now sought to be cured. By projecting a guard flange, such as 21 or 22, across the path of the disturbing air currents they will break over its edge and enter the ports instead of inducing an outward flow therethrough.

I do not positively assert the, precise nature of the action which takes place, but from actual tests I am able to say definitely that When the induction ports are guarded by an outstanding plate, flange or ledge projecting substantially perpendicular to the direction of movement of the descending currents, the disturbance of circulation of thelamp is not interfered With. I therefore use the term substantially horizontal as defining the positioning of the plate in i this broad sense. Nor do'I Wish to be limited to the particular: construction or constructions disclosed,

in the drawingsyas any element for guarding the induction ports having an edge acrosswhich the descending currents must cut, Will come Within the 'scopeof the invention. I I v f j I claim as my invention 7 1'. In atop draft' lamp, in combination, a body having a'dome provided With lateral air induction ports and a central discharge flue, and a shieldplate projecting substan-v tially horizontally from the dome.

Copies ofthis patent may be obtained for 2; In a top draft lamp, in combination, a body having lateral induction ports at its upper end and a central discharge flue, and a shield plate projecting substantially horizontally and guarding the induction ports against vertically moving air currents.

3. In a top draft lamp, in combination, a body having lateral induction ports at its upper'end, and a cap inclosing the upper end of the body and depending below the ports and being open at its lower end and having at such end an outstanding substantially horizontal flange. V

4. In a top draft lamp, in combination, a body having its upper end contracted to form a domeand havinglateral induction 5. -In a top draft lamp, in combination,

' a body having'a dome provided with lateral air induction ports and a central discharge fine, and a shield attached to the dome above the ports andcomprising a substantially horizontal outstanding plate.

WILLIAM S. HAMM.

five cents each, by addressing the Commissioner of Eatents, Washington, D; 0." w r 

